CH175C Soil Characterisation Site data sheet DEWNR Soil and Land Program
GRADATIONAL LOAM OVER CLAY ON WEATHERED ROCK
General Description: Medium thickness brown sandy loam to loam over a gravelly sandy clay loam to clay loam grading to red or orange well structured clay over weathering fine grained basement rock
Landform: Rolling low hills
Substrate: Weathered shale
Vegetation: Eucalyptus oblique forest.
Current land use - viticulture
Type Site: Site No.: CH175C 1:50,000 mapsheet: 6628-2 (Onkaparinga)
Hundred: Onkaparinga Easting: 302200
Section: Northing: 6136530
Sampling date: 09/12/2012 Annual rainfall: 920 mm average
Lower slope of low hill, 12% slope. Elevation is 510 m, with SW aspect. Firm surface.
Soil Description:
Depth (cm) Description
0-15 Dark reddish brown friable sandy loam with strong granular structure. Gradual to:
15-50 Dark reddish brown firm loam with moderate granular structure. Clear to:
50-70 Reddish brown firm clay loam with strong sub angular blocky structure. Gradual to:
70-100 Reddish brown firm light medium clay with strong subangular blocky structure and 10% shale fragments. Gradual to:
100-120 Weathering shale.
Classification: Melanic, Eutrophic, Red Dermosol; medium, slightly gravelly, loamy / clayey, deep
CH175C Soil Characterisation Site data sheet DEWNR Soil and Land Program
Summary of Properties
Drainage: Moderately well drained. No part of the profile is likely to remain wet for more than a week or so at a time.
Fertility: Inherent fertility is moderate, as indicated by the exchangeable cation data. CEC of 10 cmol(+)/kg in deep subsoil indicates that the soil’s clay minerals can satisfactorily retain nutrient elements. Retention capacity in the surface is high due to organic carbon levels.
Phosphorus levels are slightly low, with good P holding capacity. Levels of copper and zinc are high in surface soil, and magnesium levels are high under the drippers.
pH: Alkaline at the surface, acidic with depth. This trend is presumed to be caused by alkaline irrigation water.
Rooting depth: Moderate to good root growth to 100 cm.
Barriers to root growth:
Physical: There are no apparent physical barriers above the basement rock.
Chemical: There are no apparent chemical barriers, other than slightly elevated salinity at the surface (caused by irrigation water).
Waterholding capacity: Approximately 115 mm (total) in potential rootzone (to 100 cm), with readily available capacity (RAW) of approximately 45 mm.
Seedling emergence: Good.
Workability: The surface soil is readily worked.
Erosion Potential:
Water: Moderately high due to land slope. Perennial crop with good ground cover minimises hazard.
Wind: Low.
Laboratory Data
Depth cm
pH H2O
pH CaC12
Ext.
Al mg/kg
EC 1:5 dS/m
Cl mg/kg
Org.C %
NO3
mg/kg Avail.
P mg/kg
PBI Avail.
K mg/kg
SO4-S mg/kg
Boron mg/kg
Trace Elements mg/kg (DTPA)
CEC cmol (+)/kg
Exchangeable Cations cmol(+)/kg
ESP
Cu Fe Mn Zn Ca Mg Na K
Under
Drip 8.1 7.4 - 0.32 199 3.66 13 32 198 490 23.0 1.2 29.7 52 16.5 16.6 29 20 6.3 1.6 1.2 5 Between
Drip 7.3 6.8 - 0.31 231 4.16 38 27 181 578 11.8 1.0 20.5 31 7.05 5.22 24 21 1.6 0.48 1.4 2 Mid Row 7.1 6.5 - 0.14 75 4.26 20 12 155 360 6.6 1.0 12.2 38 6.65 2.68 24 21 1.5 0.14 0.8 1
0-15 7.5 7.0 0.27 0.24 146 3.61 36 46 139 609 10.0 1.1 21.8 125 23.5 6.47 23 18 2.4 0.41 1.6 2 15-27 7.1 6.5 < 0.20 0.16 - 2.48 9 16 172 406 5.1 0.7 5.0 26 2.05 3.27 15 12 1.6 0.33 1.1 2 27-45 6.3 5.4 < 0.20 0.05 - 0.84 4 6 182 153 7.8 0.5 1.3 20 0.65 1.33 11 5.6 4.3 0.33 0.4 3 45-90 5.8 4.9 0.34 0.04 - 0.71 2 2 - 120 13.3 0.6 0.6 13 0.49 0.51 11 3.3 6.7 0.33 0.3 3
Note: Trace elements in 0-15cm layer analysed using EDTA.
CEC (exchangeable cation capacity) is a measure of the soil's capacity to store and release major nutrient elements.
ESP (exchangeable sodium percentage) is derived by dividing the exchangeable sodium value by the CEC.
Further information: DEWNR Soil and Land Program
